Mounting for a rotary mill



Sept? 23, 1958 P. L. SCHOONJVER 2,853,246

MOUNTING FOR A ROTARY MILL 4 Sheets-Sheet 1 INVENTOQ PH UL. L.SCHOONOVEI? BY H/S H TTOQNEYS.

Filed July 20, 1953 P. SCHOONOVER 2,853,246

MOUNTING FOR A ROTARY MILL Sept. 23, 1958 4 Sheets-Sheet 2 Filed July20, 1953 BY HIS BTTORNEYJ. HARRIS, /(/c H, Fos Tami HfiRR/S Filed July20, 1953 Sept. 23, 1958 P. L. SCHOONOVER 2,853,246

MOUNTING FOR A ROTARY MILL 4 Sheets-Sheet 3 INVENTOR. Paul. L.\SCHOONOVEJ? aY HIS arrow/Ems. Hnems, K15 CH, Fos T528: HnRR/s P 23, 5 4P. L. scHo o NovER 2,853,246

' MOUNTING FOR A ROTARY MILL I 1 Filed July 20, 1953 f" 4 Sheets-Sheet 4/NVNTO I I PAUL L.5cH0oNovR l BY HAS ATTORNEYS.

I HARRIS, KIEChQFOJTER8zHH was I Patented Sept, 23, 1958 Phi MOUNTINGFOR A ROTARY MILL Paul L. Schoonover, Los Angeles, Calif., assignor toMonolith Portland Cement Company, Los Angeles, Calif., a corporation ofNevada Application July 20, 1953, Serial No. 369,062

8 Claims. (Cl. 241-178) This invention relates to grinding mills, andmore particularly to the larger types which are rotated upon horizontalaxes for grinding by tumbling whereby to reduce to appropriate sizes rawmaterials such as limestone employed for the making of Portland cement.

A particular object of this invention is to improve grinding techniquesfor raw materials of the indicated nature, so that very large rawmaterials may be properly reduced simply by tumbling, and without thenecessity for use of balls or rods as commonly employed in operations ofthis general type wherein the grinding apparatus works upon a horizontalaxis.

Another object of this invention is to provide in the type of millindicated appropriate constructions suitable for very large diametermills, for example heavy, tumbling mills having diameters in the orderof twelve feet to fifteen feet.

It is a further object of this invention to produce heavy structures ofthe stated nature working upon horizontal axes wherein very highefliciency is obtainable and in which such high efficiency may beaccomplished through the medium of high cascading or tumbling rates,such as 15 R. P. M. to 20 R. P. M. of the mills themselves. Rates ofthis magnitude are rated as very high for apparatus of this type.

It is a further object of the invention to provide mills which shallafford very long apparatus life while at the same time affording veryhigh efiiciency.

Another object of the invention is to provide efiicient supports at fourpoints of each mill of the indicated nature, each mounting beingconstructed independently of the other three mountings and each mountingbeing adjustable independently of the other three mountings. Suchindependent adjustments provide against undesirable thrusts betweenrails upon a mill shell by which the mill is supported and flangedwheels which in turn support the rails and the mill and areindependently driven as by electric motors for the purpose of rotatingthe mill.

Heavy mill constructions of this character are in one form accomplishedthrough the medium of an adjustable frame means at each of the fourmounting positions. Each mounting includes, for example, a pair ofvertical wheels operating upon a horizontal axis, the frame supportingthis pair of wheels being rotatable horizontally about a heavy verticalpivot pin fixed in a suitable underlying base and disposed at the exactvertical geometric center of the pair of wheels. A remote portion ofeach frame is provided with adjusting means to swing the frame aboutsaid vertical center provided by said vertical pivot pin. Heavy screwmeans may be used for swinging such remote portion of the frame. Theseframes and their respective pairs of wheels are in turn arranged inpairs at the opposite ends of the mill, so that the mill at each end isborne between the two spaced pairs of wheels on the respective spacedframes, thus providing the four required points of support. In addition,heavy tie means, such as appropriate turnbuckle means, are employedbetween the frames of each co-operating pair of frames at the respectiveends of the mill in line with their pivots to absorb lateral thrustsupon the respective pivot'pins, which thrusts would otherwise exist byreason of the spreading tendency of the weight of the mill directeddownward into the underlying space intervening between the respectiveframes.

Other objects of the invention and various features of constructionthereof will become apparent to those skilled in this art upon referenceto the following specification and the accompanying drawings whereincertain embodiments of the invention are illustrated.

In the drawings:

Fig. 1 is a side elevation of a large tumbling mill mounted inaccordance with this invention and showing the positioning of themounting means for each pair of supporting wheels in two positions atone side of th'e'mill, and also indicating the individual drives foreach pair of supporting wheels;

Fig. 1A is a vertical sectional detail of the rail and wheel arrangementand construction;

Fig. 2 is in general an end elevation, as indicated by the line 2--2 ofFig. 1 and showing the positioning of the two pairs of wheels at one endof the mill and the relationships with the corresponding drive motors;

Fig. 3 is an end view of the inner ends of the mountings of two pairs ofwheels at one end of'the mill, as indicated by the line 3-3 of Fig. 1;

Fig. 4- is a top plan View of the entire supporting 'structure of Fig. 1with the mill itself removed;

Fig. 5 is a vertical section taken on the staggered line 5-5 of Fig. 4to indicate the positioning and mounting of the parts of the mountingfor one pair of wheels at one of the four mounting positions of Fig. 4,this section being taken on a larger scale than the plan of Fig. 4;

Fig. 6 is principally a plan view, as indicated by the line 66 of Fig.5, on the same scale as Fig. 5, to show the mounting structure at therespective position of the mill; and

Fig. 7 is an end elevational detail, on a somewhat enlarged scale takenfrom the lines 7--7 of Figs. 5 and 6.

The drawings illustrate a rotary tumbling mill 10 which is provided witha conventional or preferred cylindrical shell 12 about which is securedadjacent each end a pair of mounting rails 14. In cross section, each ofthese mounting rails is that of an ordinary railroad rail. Each rail 14is supported upon two spaced wheels 15, one of which is disposed at eachside of the mill as seen in Fig. 2, as well as in Fig. 4, the two wheels15 at each mill position for the respective pair of rails 14 being thusarranged in pairs as seen in Fig. l in elevation and in Fig. 4 in plan.In the preferred form illustrated, the flanges of the wheels of eachpair are disposed at 0pposite sides of the heads of the respective railsso as to resist tendency of the mill to slip longitudinally in eitherdirection. The rails 14 might be shrunk in position on the shell 12, butconveniently they are formed in a plurality of sections bolted togetherwith tie plates and let into slight, annular recesses, or equivalentretaining channels, provided in the mill shell 12, approximately asindicated in Fig. 1A. This figure shows the usual ball or head of therail 14, its webb 16 and base 18, and each wheel 15 is shown as havingthe usual flange 15a. The contact faces of the rail heads and the wheelsare desirably flattened as illustrated so that the contact points willbe in axially directed lines rather than as lesser spots which would beprovided if curves and slopes in the respective faces'were provided.

Each of the pairs of wheels 15 is independently mounted on 'anindividual frame generally indicated at 20, there being therefore foursuch frames 20. Each such frame 20 is carried for pivotal adjustmentupon a fixed subframe or base 22.. Each sub-frame 22, as best indicatedin Fig. 5, is provided with a fixed well member or sleeve 24 and in thissleeve 24 there is positioned a heavy pivot pin 25 which extends upwardinto a sleeve 26 axially aligned .with the sleeve -24 and the pin 25 infixed position in the respective adjustable frame 20. As an indicationof the nature of the relatively massive construction which is employedfor very large mills of the nature herein indicated, which may be forexample twelve feet or fifteen feet in diameter, the diameter of thepins 25 may be about six inches and these pins consist of a section ofsteel rod. At the opposite end of each adjustable frame 20 there ismounted an individual motor 30 for driving the respective pair of wheels15, the drive shaft of this motor leading to a suitable gear reductioncase 32 containing the necessary reduction gears which are in turnconnected to a drive shaft 33 for the respective pair of wheels 15 asprobably best indicated in Fig. 4. Horizontal movement of the end ofeach frame 20 with respect to the corresponding end of its base 22 iseffected through the medium of adjusting screws 35 carried in brackets36 fixed on the opposite sides of the respective portion of therespective stationary base 22 and bearing against opposing members onthe under side of the respective adjustable frame 20. Thus, by lettingolf .one screw 35 and advancing the opposite screw 35 in any instance,the adjustable frame 20 may be moved about its pivot pin 25 as requiredto effect exact positioning of the respective wheels 15 in relation tothe sides of the rails 14 with which they engage. Such adjustment isespecially necessary with respect to the high wheels 15 seen at the leftof Fig. 2, by reason of the fact that such pairs of wheels are desirablypositioned for maximum driving efiiciency at a higher lever than theopposite pairs of wheels 15 because of the nature of the drive causingthe mill shell to rotate at a high rate in a clockwise direction asviewed in this figure. With respect to the pivot pins 25, it is notnecessary that they extend all the way up through the respective sleeves26, and the resultant spaces above the tops of the pins 25 and withinthe sleeves 26 desirably provide appropriate cavities 37 for grease orother lubricant, the tops of these cavities being conveniently sealed bymeans of interfitting covers 38 (Fig.

In order to remove from the pivot pins 25 excess lateral thrust beingapplied thereto by reason of the weight of the mill which is directedinto the space between the opposing pairs of wheels at each end of themill, appropriately heavy tie rods 40 are desirably employed. These tierods are conveniently in the form of heavy turnbuckles whose ends arefixed to portions of bearing supports 42 for the wheels 15, as throughthe medium of brackets 43 and pivot pin connections 44. These arealigned in the same vertical planes as contain the axes of therespective pivot pins 25, and, by tightening the nuts 45 of theseturnbuckle-type tie rods 40, all unbalancing lateral thrust upon theupper portions of the pins through the adjustable frameworks 20 isrelieved.

By this arrangement of individually adjustable mountings for each pairof wheels 15 at the four supporting positions of the mill 10 very large,heavy mill structures may be employed which may be rotated at relativelyhigh rates so that a high degree of cascading of the tumbling materialstherein may be elfected.

As a result very large raw materials, such as limestone chunks havingdimensions around one foot in greatest length, or even up to three feet,may be readily handled without crushing, and adequate reduction in sizefor the purpose of production of Portland cement or the like easily andquickly accomplished with coincident long life of the mill structure.

From the standpoint of the detailed structural features and mountings ofthe upper, adjustable wheelsupporting frames 20 and their lower fixedsupporting frames 22, it has been indicated that, as illustrated in 4Fig. 2, and as also indicated in Fig. 3, the wheels lying on the side ofthe direction of rotation as indicated by the arrows A should be higherfor the purpose of attaining maximum driving efficiency from the motors30 and rotating efiiciency of the mill 10. As a consequence a concretebase 50 carrying the frames for the higher wheels 50 is disposed at ahigher level than a concrete base 52 carrying the opposite frames 20 and22. The lower frames 22 are constructed of suitable upper and lowerplates 53 and 54 respectively, and these lower plates are in turn boltedas indicated at 55, and through the medium of such spacers 56 as may beneeded, to the underlying concrete bases 50 and 52.

The upper plates 53 are appropriately fixed to and mounted upon thelower plates 54 as through the medium of I-beams 58. The upper frames20, which are adjustable about the pivot pins 25 as described, are ingeneral similarly composed of upper and lower plates 60 and 62 suitablyconnected as by means of I-beams or the like 64. While connecting boltsor the like 65 may be used to maintain suitable sliding contacts of thelower plates 62 of the upper frames 20 with the upper plates 53 of thelower, fixed frames 22, appropriate lostmotion slots 66 are, however,necessarily provided in either or both of such contacting plates topermit the swinging movement required about the pivot pins 25. Theinterfaces providing the bearing surfaces between such upper bearingplates 53 and lower bearing plates 62 are, of course, preferably to beadequately lubricated as may be required to effect necessaryadjustments.

As indicated in Fig. 1, the mill may be fed by any suitable hopper orfeed neck 70 of appropriate size carried on any convenient support 72and leading into a conventional or other throat member 74 on the usualmill wall at the feed end. Similarly, as indicated in Figs. 1 and 2, themill may be discharged through an annular series of screens 75 coveringdischarge openings 76 in the discharge end 77 of the mill. The fines ofthe ground material passing the screens 75 pass through adjacentcylindrical horizontally extending screens 78 on the end of the mill anddrop into a discharge chute 80 at the lower end of a stationaryenclosing housing 82 for the screens 78. The retained coarse materialsare discharged from the screens 78 into a corresponding annular seriesof receivers 84 each of which feeds upon mill rotation to a centralreturn cone 85 directed into a flaring return spout 86 projectingthrough a central opening in the end wall 77 to return the oversize backinto the mill for further grinding. The rotating screens 78, receivers84, cone 85 and return spout 86 are assembled as a unit and secured tothe end wall 77 as by bolts 88.

By the means and method herein described, the relatively high speed ofrotation develops a high cascading rate for large materials whicheffects rapid grinding without the use of the balls or rods commonlyused for grinding raw materials for cement making and the like in thistype of mill.

Also, with heavy constructions and large diameters, such as indicated,hiwh speed tumbling of large and heavy materials is readily accomplishedwithout injury to the mill or its mounting and driving means.

By providing separate mounts for the mill and providing separate motorsfor driving the supporting wheels of the different mounts, thoroughlyaccurate adjustment of each pair of the supporting and driving wheels 15with respect to the carrying rails 14 of the mill is assured. Also, highspeed rotation of the heavy mill is easily effected through the mediumof the several motors 30 which will normally be load-balanced orsynchronized as may be required. Oversize materials discharged throughthe end screens 78 are fed back to the mill through the central spout 86by mill rotation as described.

In operating the tumbling mill of this invention it is possible to feedlarge raw materials to the mill because of its unusually large diameter,such as 12 to 15 feet.

Thus, crushable run-of-mine materials, such as limestone, are handledwith great savings in previously required preliminary treatment. Allbreaking and crushing is therefore effected merely by tumbling the feedmaterial, which is retained in the mill until reduced to the requiredfine particle size. Since the mill described may be rotated at highrates of rotation for this art and this type of mill, e. g. 17 to 20 R.P. M., a high cascading effect is accomplished by reason of the factthat both large and small materials are carried high up the mill side inthe direction of the arrow of Fig. 2, so that the materials fall backonto lower materials in the mill with impact sufficiently great toproduce the necessary grinding or crushing action. If elevatingprojections are needed on the mill interior, they are used. Properadjustment of the supporting Wheels 15 is readily accomplished with themeans described, Wear of the parts being thereby reduced to a minimum,and the described rapid rotation with the four motors 30 and incidentalhigh cascading efiects are easily obtained. Since the mountings at theopposite ends of the mill are well spaced, the properly reduced, fineproduct is conveniently discharged from the respective mill end merelyby disposing the downwardly directed chute 80 to discharge between therespective mountings at a position adjacent but forward of therespective wheels 15 and their connecting tie rods 40. The product isthen led off to a point of disposition by any conventional or preferredconveyor means, or otherwise as desired.

I claim as my invention:

1. A rotary mill which includes: a rotary mill shell disposed on ahorizontal axis; rails disposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being located adjacent to each end of saidmill, the mountings of each of said pairs being located on oppositesides of said mill shell; flanged wheel means carried by each of saidmountings, said wheel means engaging said rails so as to support saidmill shell; stationary base means for each of said mountings; pivotmeans, connecting each of said base means and the corresponding one ofsaid mountings, each of said pivot means having a vertical axiscoinciding with the vertical center of said wheel means on saidmounting; and means for turning said mountings upon each of said basemeans around said pivot means so as to align said wheel means with saidrails.

2. A rotary mill which includes: a rotary mill shell disposed on ahorizontal axis; rails disposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being adjacent to each end of said mill, themountings of each of said pairs being located on opposite sides of saidmill shell; flanged wheel means carried by each of said mountings, saidwheel means engaging said rails so as to support said mill shell;stationary base means for each of said moutings; pivot means connectedto each of said base means and the corresponding one of said mountings,each of said pivot means having a vertical axis coinciding with thevertical center of said wheel means on said mountings and each of saidpivot means comprising a pivot pin mounted in each of said stationarybase means so as to extend therefrom and a bearing sleeve located ineach of said independent mountings for receiving one of said pivot pins;and means for turning said mountings upon each of said base means aroundsaid pivot means so as to align said wheel means with said rails.

3. A rotary mill which includes: a rotary mill shell disposed on ahorizontal axis; rails disposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being adjacent to each end of said mill, themountings of each of said pairs being located on opposite sides of saidmill shell; wheel means carried by each of said mountings, said. wheelmeans engaging said rails so as to support said mill shell; stationarybase meansfor each of said mountings; pivot means connected to each ofsaid base means and the corresponding one of said mountings, each ofsaid pivot means having a vertical axis and each of said pivot meanscomprising a pivot pin mounted in each of said stationary base means soas to extend therefrom and a bearing sleeve located in each of saidindependent mountings for receiving one of said pivot pins, the upperportion of each of said sleeves being provided with a well adapted tocontain a lubricant, the vertical axis of each said pivot meanscoinciding with vertical center of each of said wheel means of saidmountings; and means for turning said mountings upon each of said basemeans around said pivot means so as to align said wheel means with saidrails.

4. A rotary mill which includes: a rotary mill shell disposed on ahorizontal axis; rails disposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being located adjacent to each end of saidmill; wheel means carried by each of said mountings, said wheel means oneach of said mountings engaging one of said rails so as to support saidmill shell; stationary base means for said mountings; vertical pivot pinmeans connecting each of said base means and the corresponding one ofsaid mountings; and tie means extending between the mountings of each ofsaid pair of mountings, said tie means being aligned with said pivot pinmeans, said tie means serving to absorb thrust strains tending to movesaid mountings away from one another.

5. A rotary mill which includes: a rotary mill shell disposed on ahorizontal axis; rails disposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being located adjacent to each end of-saidmill; wheel means carried by each of said mountings, said wheel means oneach of said moutings engaging one of said rails so as to support saidmill shell; stationary base means for said mountings; vertical pivot pinmeans connecting each of said base means and the corresponding one ofsaid mountings; tie means extending between the mountings of each ofsaid pair of mountings, said tie means being aligned with said pivot pinmeans; said tie means serving to absorb thrust strains tending to movesaid mountings away from one another; and means for turning saidmountings upon said base means about said pivot means so as to alignsaid wheel means with said rails.

6. A rotary mill which includes: a rotary mill shell disposed on ahorizontal axis; rails disposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being adjacent to each end of said mill, themountings of each of said pairs being located on opposite sides of saidmill shell; wheel means carried by each of said mountings, said wheelmeans engaging said rails so as to support said mill shell; stationarybase means for each of said mountings; pivot means connected to each ofsaid base means and the corresponding one of said mountings, each ofsaid pivot means having a vertical axis and each of said pivot meanscomprising a pivot pin mounted in each of said stationary base means soas to extend therefrom and a bearing sleeve located in each of saidindependent mountings for receiving one of said pivot pins; means forturning said mountings upon each of said base around said pivot means soas to align said wheel means with said rails; and tie means extendingbetween the mountings of each of said pairs of mountings in line withsaid vertical axis of said pivot means for absorbing thrust strainsdirected toward said pivot means by reason of the weight of said millshell.

7. A rotary mill which includes: a rotary mill shell deposed on ahorizontal axis; rails deposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneof said pairs of mountings being located adjacent to each end of saidmills; wheel means carried by each of said mountings, said wheel meanson each of said mountings engaging one of said rails so as to supportsaid mill shell; stationary base means for said mountings; verticalpivot pin means connecting each of said base means and the correspondingone of said mountings, each of said pivot pin means having a verticalaxis coinciding with the vertical center of said wheel means on saidmounting; and tie rod means extending between the mountings on each ofsaid pairs of mountings, said tie rod means being aligned with saidpivot pin means, said tie rod means serving to absorb thrust strainstending to move said mountings away from one another.

8. A rotary mill which includes: a rotary mill shell deposed on ahorizontal axis; rails deposed around said mill shell adjacent to theopposite ends thereof; pairs of independent mountings for said mill, oneofsaid pairs of mountings being located adjacent to each end of saidmills; wheel means carried by each of said mountings, said wheel meanson each of said mountings engaging one of said rails so as to supportsaid mill shell; stationary base means for said mountings; verticalpivot pin means connecting each of said base means and thecorrespondingone of said mountings, each of said pivot pin means having a verticalaxis coinciding with the vertical center of said wheel means on saidmounting; and tie rod means extending between the mountings on each ofsaid pairs of mountings, said tie rod means being aligned with saidpivot pin means, said tie rod means serving to absorb thrust strainstending to move said mountings away from one another; means for turningsaid mountings upon said base means about said pivot pin means so as toalign said wheel means with said rails.

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